FIRST flight of the Light Combat Aircraft (LCA) prototype, more correctly,
Technology Demonstrator or TD-1 on 4 Jan 2001 has gone down in India's
aviation history as a landmark event. All those associated with the development
of the LCA especially the scientists, engineers and others, deserve the
nation's unreserved congratulations and felicitations.
But there will always remain a strong segment of informed opinion that
will find it difficult to applaud this indigenous effort of the DRDO's
subordinate organisation, the Aeronautical Development Agency (ADA), India's
premier aerospace company HAL and last but not least the National Flight
Yet no one can deny that the much delayed flight of the LCA will give
Indian scientists and engineers the long needed self-confidence to continue
their efforts to operationalise the fledgling experimental technology
demonstrator quickly, so it can enter operational service with the IAF
on schedule. Inevitably, there will be many challenges before that happens
and as in the past, the Doubting Thomas will take great pleasure in highlighting
the LCA already obsolescent?
we dependent on the US for the continued supply of the General Electric
GE-F-404 engine? How can we get more of these if the sanctions remain
in place? We are far from developing the multi-mode radar
- Nor is
there any sign of the indigenous Kaveri jet engine of the Gas Turbine
Research Establishment (GTRE) Bangalore being available for some time
- In any
case, the LCA has only a limited range and payload since it was meant
to replace the venerable MiG-21 fighter of the '50s vintage
- The full
authority quadruplex digital fly-by-wire flying control system also
requires proving trials and debugging throughout the entire flight envelope,
as do the myriad components of the aircraft
of the various weapons and armaments and firing trials will also pose
a major challenge as some of the missiles may come from Russia and the
PGM from Western sources
- It is
also likely that the manufacturers of the hundreds of small but vital
components will find it difficult to remain on the programme unless
the major, and probably the only customer, the Indian Air Force places
a firm demand on HAL for a sizeable number of the combat aircraft.
many other questions and doubts about the future of the LCA are indeed
valid and some workable solutions would have to be found soon. Before
we do that, however, we need to take a brief look at the history of India's
aeronautics industry to understand and assess the chances of all these
seemingly impossible tasks being performed in time and more importantly,
to the satisfaction of the IAF because, in the ultimate analysis, it is
the IAF that will employ the LCA in any future war.
What needs to be reiterated here is the fact that the future of the Indian
Aeronautics Industry, especially HAL, is intricately linked to the future
of the IAF. No modern state can hope to face the challenges of a newly
globalizing and hence uncertain world without its modern air power being
deeply rooted in indigenous aeronautical capability. HAL has a nearly
60-year long record of being the premier aerospace industry in South Asia.
It produced the HT-2 piston engine trainer as far back as in 1951. It
licence-produced a whole host of aircraft and helicopters of different
types and pedigrees and was one of the first to design a contemporary
fighter the HF-24 albeit with the help of a German designer Dr. Kurt Tank.
The HF-24 first flew as early as June 1961 and despite the many teething
problems, performed creditably in the 1971 Indo-Pak war. The lack of a
suitable engine however put paid to its future and it was finally retired
from the IAF in 1986.
The slow progress in the Kaveri engine may put similar stumbling blocks
in the path of the LCA. The indigenously developed multi-mode radar with
state-of-the-art capabilities is also likely to take time before it reaches
production stage. A modern aircraft like tne LCA depends very largely
on the airborne radar without which its agility and immense maneuvrability
are of little value. Modern avionics, including the radar, are in fact
the heart of a modern combat aircraft.
The LCA also has another unique feature in the form of a light-weight
wing made of Carbon Fibre Composite (CFC) materials. Although the TD-1
& 2 wings were produced with the help of Alenia, an Italian company
specialising in CFC technology, indications are that India has already
developed this capability and will soon be able to produce the CFC wing
without any further foreign support. It is reported that the ADA at Bangalore
had funded and assisted some 180 Indian manufacturers to develop and fabricate
the thousands of small parts of varying complexity that have gone into
the LCA, and from all accounts they have done a commendable job.
It can thus be seen that continued progress of the LCA programme will
impact on the future of many other fledgling and veteran programmes of
the Indian aeronautics industry As is well known, India's space and missile
programmes have shown remarkable progress in the last decade or so and
there is every reason to believe that the spin-offs of their success will
undoubtedly help the aeronautics industry. What needs to be remembered,
however, is that unlike the missile which is a single shot or one-time
use weapon, manned combat aircraft require a far higher reliability quotient.
It is thus only natural that many glitches would have to be removed before
the LCA is ready to enter operational squadron service, where it will
be flown by relatively inexperienced pilots through the full flight envelope
and not by a test pilot flying a predetermined profile. The flight of
the TD-1, in that sense, was just the crossing of the first hurdle in
a long marathon on an uneven road.
Coming back to the Kaveri, it is reported that the engine is ready to
be flown on a flying test-bed in Russia. It is only after the successful
completion of this crucial test that the development of this engine can
move apace. The Kaveri is an ambitious project given that it will be a
highly efficient engine of relatively small size but with a high thrust
output. It is but natural, therefore, for those with experience in this
field to doubt India's capability to successfully build such an engine
in a short time. It is perhaps possible to say with the advantage of hindsight
thatt India should never have abandoned her maiden venture to that was
to design and produce an engine for the HF-24 aircraft. But let it be
remembered that whenever India reached a decisive stage in indigenous
development or manufacture of high technology components and aircraft,
foreign manufacturers offered the same at very lucrative prices sometimes
on repayment terms that a developing country, facing the threats that
India did, could have ill-afforded to refuse. That is how international
forces control the destinies of smaller players.
Today fortunately, India's economy and technology base is much more sound
and the powers that be have learnt their lessons in self-reliance. In
today's market driven world of MNCs where even giants of the aviation
industry are merging with others to form even bigger business conglomerates,
it is difficult for an inexperienced regional player like India's HAL
to survive without some very clever and deft moves to remain afloat. HAL
will hopefully be gainfully occupied in producing the 124 upgraded MiG-21
bis fighters, the 140 Su-30 MKI, a large number of Intermediate Jet Trainers
as replacement for the nearly 30-year-old Kiran trainers, the Dornier,
Alloutte and many other licence produced aircraft together with components
and engines. HAL also has the task of overhauling the Mirage-2000 and
the MiG-29 fighters.
It is in addition to these varied tasks that the HAL will have to produce
the LCA prototypes and later possibly more aircraft on order. The crux
of the argument is that without a demand for at least some 50 or 60 units
of the LCA, it may be difticult for the HAL and indeed even DRDO-ADA to
continue development work on this promising but challenging experiment.
The IAF will no doubt support the programme but whether or not it can
allocate the necessary funds every year for the projected notional demand
of some 50/60 aircraft is doubtful, at least at the present moment. This
is simply because there is no guarantee that HAL will indeed produce the
numbers ordered on schedule.
To be fair, it is too early for HAL to make a commitment to complete the
production of even 20 aircraft by a definite date since the LCA is far
from a proven platform and it will be at least five years before the picture
starts to become clear. The IFC or Initial Flight Clearance is planned
only for 2005 and FFC or Full Flight Clearance for 2010. There is also
the fear of the aircraft becoming obsolete before it reaches squadron
service. Given its state-of-the-art design, however, this fear is misplaced.
In any case, it should be possible to upgrade the systems as the programme
develops. Its 300 km ROA and some 8 ton armament payload do appear to
be well short of its contemporaries. But then a light combat aircraft
to be used essentially for air defence and strike cannot be expected to
carry the same payloads as the Su-30 which is in a different class altogether.
The IAF cannot obviously wait indefinitely for equipping some four to
six of its frontline squadrons with this indigenous fighter, however promising
it may be, simply because like any air arm the IAF has to forever remain
ready to successfully fight a war that may erupt tomorrow. No Air Chief
can ever ignore that primary responsibility. Given the induction of high-tech
weapons systems in India's neighbourhood, the Air Chief is indeed in an
unenviable position. This is the Catch-22 situation that one would hope
never to get into. Neither the development of the LCA nor the short-term
defence needs of the nation can be ignored. The only possible option could
be a compromise at the least possible cost.
Considering that the Kaveri engine and the multi-mode radar are the two
major components without which the LCA cannot ever see squadron service,
India could hunt for a foreign engine and radar as an interim measure.
The Russian built RD-33 presently fitted on the MiG-29 is being upgraded
to RD-93 for single engine use. (The MiG-29 has two RD-33 engines) The
French M-88-2/3 an engine fitted on the Rafale is also in the same class
and may be available. Both these engines have nearly the same dimensions
and thrust rating as the GE F-404 and who knows, with the change of guard
at the White House, sanctions may be lifted even earlier and a suitable
engine like the P&W F-100 or GE110 (presently fitted on the F-16 CIDs)
may be available from the USA.
There are two possible candidates for the multi-mode radar, the Israeli
ELTA EL/M-20022 or the Russian Phazatron Kopyo. The former is the better
of the two but the latter is being fitted on the upgraded MiG-21 bis aircraft
and it may be easier and even economical to get some 50 additional pieces
from Moscow, provided of course the IAF accepts the arrangement. It can
be hoped that with the likely addition of sizeable numbers of Su-30 MKIs
and even some Mirage-2000 aircraft and the already upgraded MiG-21s and
MiG-27s, it might not be too difficult to convince the IAF. This is where
HAL, DRDO and indeed the Ministry of Defence will have to play a constructive
role and give forecasts that are genuine and realistic or else the IAF
will once again feel let down.
In the past too, it was not for lack of understanding of the problems
of a nascent aeronautics industry that the IAF appeared to shop for foreign
aircraft, but mainly because the production schedules were not strictly
adhered to. As is well known, any indigenous aircraft industry must first
win the confidence of the nation's air force and only then can it expect
the air force to support it. There are many examples of the most highly
advanced combat aircraft not being accepted for export untill that country's
air force first inducted them.
In the circumstances, it seems that the IAF would do well to support the
development of the LCA with a firm order for some 50 aircraft, but only
after the developers and the producers provide a realistic schedule. It
would not be fair to allow the former to exercise a veto every time the
latter wants some new equipment because finally when the chips are down,
it is the IAF that has to defend the nation's airspace. There are no runners-up
in this game. Unless India's decision-makers collectively assist and promote
it, the KH-2001 may remain just a costly technology demonstrator.
The author is a Senior
Fellow at the Institute of Defence Studies & Analysis
(c) Indian Defence Review
Editor's Note: The article is interesting
when seen in the light of reports that Russia has offered to help develop
the LCA. The offer was made at the recently concluded AeroIndia show in
Bangalore by aircraft makers MiG and Sukhoi.
Russia's Air Force Chief General Anatoly Kornukov, who was in Delhi briefly
before flying to Bangalore, is reported to have discussed the issue with
India's Air Chief Yeshwant Tipnis and Defence Secretary Yogendra Narain.
He was later quoted by The Times of India as saying: "I have certain things
to propose but I don't want to make these details public." Russia is not
entirely new to the LCA programme. The indigenously developed Kaveri engine
is undergoing extensive trials in Russia and is now expected to be flight
tested on a Russian TU16 aircraft. Defence Minister George Fernandes has
welcomed Russia's offer to help productionise the LCA but said his ministry
is also exploring the possibility of involving some South-east Asian countries
in the programme in an attempt to share costs.
The Russian offer lends weight to Air Commodore Phadke's argument that
whenever India was close to a breakthrough in areas of defence technology,
foreign consortiums would step in with offers to sell the same at considerably
reduced rates. In the process, Indian industry and engineers lost out.
But until details of the Russian offer are known, it would not be fair
to attribute motives to them.
It's been suggested that the Russians may have recommended modifications
to the Kaveri. Such modification may require the assent of the US since
the Kaveri is based on the GE 404 engine technology. Developing an entirely
new engine for the LCA could delay it even further. Besides, Russian involvement
in the LCA deepens India's dependence on Russian technology and equipment.
Barring the Mirage and Jaguars, Russian fighters form the backbone of
the IAF (124 MiG 21Bis now being upgraded, 165 MiG 27s and 74 MiG 29s
also due for upgrade and the proposed acquisition of around 28 MiG 29Ks
for the Indian Navy). However, it's also true that Russia has gone far
beyond LCA technology and would not find it difficult to develop something
It could also be that Russia's proposal maybe intended to open the doors
for the possible sale of the MiG Advanced Trainer. The trainer was on
show at AeroIndia and Russian representatives have hinted at producing
it in India. The delay in the acquisition of the Hawk AJT, because of
India's insistence that it have no American components, has added to rumours
that the deal may fall through. Reports from Moscow have quoted unnamed
sources as claiming that the AJT deal is in fact off (which is not the
case). Ironically, the LCA was the first major US involvement in such
a high profile Indian defence programme. The agreement signed with Lockheed
Martin in 1988 envisaged that company developing the flight control systems.
If things had proceeded smoothly, the LCA would have been powered by technology
equivalent to the earlier variants of the F 16. Unfortunately, US sanctions
put paid to that. The recent US lifting of sanctions on the sale of spares
for the Indian Navy's Seaking helicopters has revived hopes of a change
in their attitude to the LCA programme also.
design of the LCA was based on a metallic body, but ambitious men wanted
to use composites. The Indian Air Force opted for a metallic fuselage
with traditional technology instead of experimenting with unproven composites.
After all, only about half a dozen countries around the world, Italy's
Aliena, Germany, France's Mirage and Air Bus, Britain's British Aerospace
and Jaguar - are well versed with handling composite technology. The US
depends on its very advanced metal technology and less on composites,
though about 45 per cent of the F-22 Raptor aircraft comprises of composites.
Advanced composite units at NAL and HAL were established. Both have been
instrumental in supporting HANSA, SARAS and the LCA. Prahlad says that
bridging a technological gap - as in handling the composites - is more
important than satisfying the design aspects. Assemblies with fasteners,
bolts, rivets get replaced by monolithic composite components. The spin
off is easily absorbable in space launch vehicles and guided missiles,
where reusability and pilot's lives are not issues.
The use of composites results in a 40 per cent reduction in the total
number of parts: For instance, 3,000 parts in a metallic design would
come down to 1,800 parts in a composite design. The number of fasteners
has been reduced to half in the composite structure from 10,000 in the
metallic frame. The composite design helped to avoid about 2,000 holes
being drilled into the airframe. Though the weight comes down by 21 per
cent, the most interesting prediction is the time it will take to assemble
the LCA -- the airframe that takes 11 months to build can be done in seven
months using composites.
Involvement of British Aerospace
A component that has curvature, bend and sharp edges may look easy to
be formed with composites. But its strength and stress-bearing capacity
at certain points is difficult to measure and to improve upon. Tooling
design is the most critical requirement in composite technology. The skin
of the LCA measures 3 mm at its thickest with the average thickness varying
between 2.4 to 2.7 mm. The skin needs to bear a force of 100 Newton per
mm. What the designers initially achieved was just 40 N/mm. With some
improvements it reached 60 N/mm. Interaction with BAe offered some solutions.
BAe is reported to have achieved 160 to 180 N/mm which was a challenge.
It came to light only later that they were working with skin thickness
of 6 mm. This was a lesson well learnt when composites were used in the
bulkhead and stiffener underneath the skin.
problem was another headache for the designers. T-pull occurs at skin
and stiffener edge. It includes two forces: One force which acts perpendicular
to a surface is referred to as 'sigma z'. The inter-lamination shear stress
the trme to assemble the LCA - the airframe that takes along the surface
is the other. The flat top of a T-joint meshes with the surface of a composite
panel. Adhesives hold them together. The 'leg' of the T joins the flat
top not in a perfect mesh - but creates a triangular void at the junction.
This is termed as the Bermuda Triangle. Forces tend to pull the leg away
from the top; the initial design could withstand only 40 N/mm. An innovative
introduction of a thin composite interface strip between the flat top
of T and the surface improved the strength dramatically to 60 N/mm. From
a basic design scheme it graduated into padded configuration and overlay
configuration. Failure was expected at the joints - which did not happen.
On the fuel tank floor, horizontal and longitudinal stiffeners cross each
other. At the point of crossing, the longitudinal members are cut out
to allow the breadth-wise members to pass through. This process is intricate
and special tooling was necessary. Stiffeners join the surface in T-joint
and need to be perpendicular to the surface - at exactly 90 degrees!
and analysis are continuing to make the T-joint stronger. Adhesives and
reinforcement are used to fill the void. Flex cores are used which not
only look simple but also elegant. Stitches to bind the flat top of the
T to the surface is another method. The recommendations
of BAe helped and further progress is foreseen. A 'duct dividing wall'
made of composites, which reduces the number of parts and fasteners, is
another indigenous effort. It was conceived against existing norms. Complex
tool is developed to work on an area measuring 3 m by 1 5 m made of composite.
Baffle frame stiffener in fuel tank needs precision engineering.
The Air Duct is a monolithic piece that needs stiffeners. Generally stiffeners
protrude outward or inward depending on the component. But the surface
of air duct is to be smooth and protrusion of stiffeners cannot be outward
lest it obstruct free airflow. So stiffeners are embedded and internal.
According to Simha the consultant, one of the 'two best parts' designed
is used where the air duct enters the fuselage, with four external and
two internal stiffeners, which replaces nearly 30 metallic components.
A conventional design could have been used. In the conventional sandwich
design, two thin skins called face sheets of 0.3 mm to 1.5 mm thickness
are separated by honeycomb struts made of aramid based nomex. The separated
space of 10 mm to 20 mm is mostly hollow. Sandwich panels are used in
under carriage door, hatches or panel covering the armament bay. Repeated
failure was encountered at the inner skin of the air intake with the sandwich
design, using metal or composite adopted until then. The other best part
is the Y-joint in the floor of the fuel tank with longitudinal stiffeners
along the body.
The Y-Joint is an innovation in the airframe of the LCA where the air
duct joins the floor of the fuel tank. Centre fuselage holds the fuel
tank which is 2.5 m long. This part needs to handle hook stress and bending
stress with the skin being 2.4 mm thick. A monolithic composite part that
replaces several metallic pieces was developed. It merges with a counterpart
at the bottom, which contains the fuel tank floor. Prevention of fuel
leakage is of prime importance. Simha conceived of a small extension at
the edge of the top piece, in a new design, which had to mesh with a similar
receptacle in the bottom part in a Y-shaped joint. One arm of the Y runs
to a length of 1.75 m along the fuel tank floor. No one was sure that
it could be manufactured to required specifications. NAL helped. With
stiffeners both inside and on the external surface, the secondary bonding
technique was successfully used to a length of 1.75 m. The scientist who
made this says: "One learns from nature. Branches of trees join the
trunk usually in a Y-joint. It must be naturally strong."
and Torque Shaft
The fin for the LCA is a monolithic honeycomb piece. No other manufacturer
is known to have made fins out of a single piece. The torque shaft for
actuating the rudder is a challenge. It is built on additive process.
The cost of manufacture reduces by 80 per cent from Rs 2.5 million in
this process. This is contrary to a subtractive or deductive method normally
adopted in advanced countries, when the shaft is carved out of a block
of titanium alloy by a computerized numerically controlled machine. A
'nose' for the rudder is added by 'squeeze' riveting.
Yet another innovative design is stiffener of hat section. It has a cross-section
that resembles a hat in sequences, it endured the tests and worked well.
A honeycomb sandwich piece measuring 400 mm in breadth was not reflecting
the required strength to withstand shear forces. Other manufacturers have
used similar designs. Within the breadth of 400 mm a hat like cross-section,
six or seven in number, successively linked in sequence in the stiffener,
is tried in the design. In fact about 30 per cent of the composite material
is carved out from the original strip. Hollow portions are created. Yet
the design proved capable of withstanding larger shearing forces. It is
an optimisation of shape. Engineers use Finite Element Analysis in optimising.
FEA computer software are available. Now, an engineer can develop new
software based on this design. Autolay -- the software used by designers
in the project -- is fondly mentioned.
5435 and 8385
Composites are used in the inner skin at air intake on section 5435 of
the front fuselage, at section 8385 of the rear fuselage and at the external
skin of rear fuselage. The policy statement stipulates that small cutouts
in the airframe are to be minimised; only large cut outs for access are
acceptable. Where the straight stiffeners did not provide the required
strength, flanged reinforcements were successfully tried. Benefits accrued
in achieving improved buckling factor and consequently effected manageable
When lightning strikes the LCA, four metal longerons stretching from end
to end, afford protection. In addition, all the panels are provided with
copper mesh. One out of five is 'bonding' bolt with gaskets to handle
Electr-Magnetic Interference. Aluminum foils cover bolt heads while the
fuel tank is taken care of with isolation and grounding.
Corrugated Composite and Test
Some components are of sheets that taper down from a thickness of 9 mm
to 3 mm. Obviously, the lamination should dwindle without losing strength.
A corrugated finish, which is meticulously achieved, is used. NAL has
the only Non-Destructive Test facility in India using ultrasonic tests
with frequency varying from 1 to 10 megahertz to test composites. It is
needed at many stages in development. Result is in the form of colour
images and is analyzed.
Indian Institute of Technology, Powai is involved in providing test boxes,
which replace a few test panels. Ultrasonic based testing is necessary
on composite surface, which does not show cracks but can have de-laminated
layers. Dent shows up on composites though the design allows for barely
visible damage to the skin, which may not grow. Moisture is absorbed by
composite but the design takes this into consideration. A portable ultrasonic
test gear is under development, which can be used in field formations.
SARAS is Thinner
The passenger aircraft under development, SARAS, has control surface that
uses composite sheet of 0.6 mm thickness. Squeeze riveting used here is
more sophisticated. Technology usable on a sheet with 3 mm thickness cannot
be directly adopted.
Plaster of paris is used to make moulds on which composite sheets of the
required thickness including the taper are shaped. Surface of the mould
needs to be absolutely plane, which is provided by smoothly machined granite
tabletops on the workbench. Templates support the plaster block on both
sides. The compound solidifies by normal sunlight. To prevent shrinking,
solidifying compound from losing its surface grip on the template, screw
and nut are inserted on the template. The nut acts as locking nut. Depending
on the complexity, the number of screw holes increase. Appropriate technology
is in use in the most sophisticated aircraft that this country has seen.
From a level of non-use, composites now form nearly half of the airframe,
which carries 30 per cent of the total weight of the aircraft. At times,
wealth of information gets poverty of attention - more so with the LCA.
May the will of each Indian fly with it!
Indian Defence Review